1. Field of the Invention
The present invention relates to an image forming apparatus and an image forming method.
2. Description of the Related Art
In a traditional image forming apparatus, the following procedures are carried out: an electrostatic latent image is formed on a photosensitive surface of a photosensitive drum as an image carrier followed by developing the latent image to be made visible on the photosensitive surface as a toner image. Subsequently, the visualized toner image is transferred to a paper, and that transferred toner image is fixed on the paper.
Also, the traditional image forming apparatus as described above can employ a well-known toner recycle technology so as to clean and remove residual toner remaining on the photosensitive drum by a cleaner portion after the toner image has been transferred onto a sheet and transport the resultant recovered toner (hereinafter, referred to as “recycle toner”) to a developing portion for recycling.
On the meantime, in the event that the size of such an image forming apparatus is intended to be entirely reduced, a fixer as a heat source and the cleaner portion are often disposed to be close to each other. In this case, the temperature of or relative to the cleaner portion is liable to elevate due to thermal influence from the fixer or the like after an image forming operation has been terminated. In particular, such a temperature elevation of the cleaner portion is remarkably manifested immediately after the termination of the image forming operation.
In the image forming apparatus employing the toner recycle technology, there often exists within the cleaner portion the recycle toner (or recovered-toner) which has been recovered from the photosensitive surface of the photosensitive body but not yet transported to the developing portion. When the temperature of the cleaner portion is elevated to excess on the condition that there exists the recycle toner therein, a thermal stress is rendered to the toner.
If the recycle toner within the cleaner portion undergoes the thermal stress as mentioned above, it is liable to clump, thereby disadvantageously leading to deterioration in picture quality (a so-called “clump-fog”) of the image formed on a paper sheet material. Further, electrical chargeability of the recycle toner is deteriorated, thereby disadvantageously leading to a so-called “fog” on the image formed on the paper sheet material.